loop_
    _rcsb_struct_link.id
    _rcsb_struct_link.vertex_id
    _rcsb_struct_link.label_comp_id
    _rcsb_struct_link.label_asym_id
    _rcsb_struct_link.label_seq_id
    _rcsb_struct_link.label_atom_id
    _rcsb_struct_link.symmetry
      C1  from ARG  A  87 NZ1 1_555 
      C1  to   GLU  A 92  OE1 1_555
      C2  from ARG  B 287 N   1_555 
      C2  to   GLY  B 292 O   1_555